-U.S. tobacco-control programs prevented nearly 800,000 lung cancer deaths in the last quarter of the 20th century, but more than three times as many could have been spared had the entire population stopped smoking in 1965, according to a landmark study released Wednesday.
The study, conducted by researchers at Rice University, the University of Texas M.D. Anderson Cancer Center and other institutions, provides the first numbers showing the life-saving effect of tobacco tax hikes, bans on smoking in public places, limiting underage access and public education campaigns.
"This study is proof of how well these programs work," said Olga Gorlova, a professor of epidemiology at M.D. Anderson and one of the study authors. "Screening is good secondary prevention, but we now know just how many deaths primary prevention can avert."
Gorlova said she hopes the findings lead to more aggressive tobacco control efforts. She singled out the need to counter tobacco companies' targeting of young people, the time when most smokers acquire the habit.
The study, published online Wednesday in the Journal of the National Cancer Institute, was based on sophisticated modeling that estimated the numbers of smoking-related lung cancer deaths from constructed tobacco-use histories of people born from 1890 through 1970. Six different models, the Rice-M.D. Anderson team's among them, reached similar conclusions.
Despite more than 40 years of tobacco-control programs, lung cancer remains the leading cause of cancer deaths for men and women, killing more than 160,000 annually in the U.S. More than 80 percent of lung cancer cases are attributed to smoking.
Gorlova called the study's estimate of smoking-related lung cancer deaths on the "low side," and stressed it did not consider the influence of smoking on other cancers and diseases, such as emphysema and heart disease.
Twin projections
To arrive at their numbers, researchers projected two scenarios -- if all smoking in the United States stopped in 1965 and if there were no change in smoking trends starting that year -- and compared them to smoking and lung cancer death data. About 2.5 million deaths would have been prevented had everyone stopped smoking, they found.
The 800,000 prevented deaths included 552,0000 men and 243,000 women.
David Sylvia, a spokesman for Philip Morris USA, said company officials couldn't comment on the study because they hadn't reviewed it. He acknowledged in a statement that smoking is "addictive and causes serious disease" and said the company agreed with established anti-smoking approaches.

"A complementary strategy, focused on the development of and appropriate communications about potentially lower risk tobacco products, may be one of the most meaningful actions that the Food & jDrug Administration can take to reduce the health effects of smoking," the statement said.

Lack of will blamed
Smoking rates have declined in America since the 1960s, when the Surgeon General's Report on Smoking and Health prompted anti-smoking interventions. In 1964, 53 percent of men and 32 percent of women smoked.
By 2008, the numbers had dropped to 23 percent and 18 percent, respectively. But the reduction has slowed in recent years. A surgeon general's report last week said steep declines in youth smoking and the use of smokeless tobacco had leveled off, a trend that the NCI's Thomas Glynn attributed to a mid-1990s complacency about anti-smoking efforts. b
Glynn said anti-smoking interventions have picked up again in recent years, particularly tax hikes and restrictions on smoking in public places. In Houston, those restrictions now extend from restaurants and bars to public parks.
Still, in an accompanying editorial in the NCI journal, Glynn asked how, over the past 100 years, "we allowed tobacco to kill and cause disease with such abandon."
"Despite knowing what works and having the science to back that up, we have often lacked the political and financial will to do what is necessary to take full advantage of our knowledge and put an end to the scourge of tobacco in our society," wrote Glynn, the NCI's director of cancer research and trends.
todd.ackerman@chron.com
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